Optical imaging lens

ABSTRACT

An optical imaging lens includes a first lens element to a fifth lens element from an object side to an image side in order along an optical axis, and each lens element has an object-side surface and an image-side surface. An optical axis region of the image-side surface of the first lens element is concave, a periphery region of the image-side surface of the fourth lens element is concave, an optical axis region of the object-side surface of the fifth lens element is convex, and a periphery region of the image-side surface of the fifth lens element is convex. EFL is an effective focal length of the optical imaging lens and TTL is a distance from the object-side surface of the first lens element to an image plane along the optical axis to satisfy 1.1≤EFL/TTL≤1.6.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention generally relates to an optical imaging lens.Specifically speaking, the present invention is directed to an opticalimaging lens for use in taking pictures or in recording videos in anelectronic device, and capable of zoom-in.

2. Description of the Prior Art

In recent years, an optical imaging lens improves along with its widerand wider applications. In addition to good imaging quality, a designwith a shorter system length and with a zoom-in function is getting moreand more important.

Accordingly, it is always a target of the design in the art to come upwith an optical imaging lens with good imaging quality, with a shortersystem length and with a zoom-in function to meet the demands which arerequested by consumers in present days for an optical imaging lens.

SUMMARY OF THE INVENTION

In the light of the above, various embodiments of the present inventionpropose an optical imaging lens of five lens elements which has reducedsystem length of the optical imaging lens, ensured imaging quality, azoom-in function, good optical performance and is technically possible.The optical imaging lens of five lens elements of the present inventionfrom an object side to an image side in order along an optical axis hasa first lens element, a second lens element, a third lens element, afourth lens element and a fifth lens element. Each first lens element,second lens element, third lens element, fourth lens element and fifthlens element respectively has an object-side surface which faces towardthe object side and allows imaging rays to pass through as well as animage-side surface which faces toward the image side and allows theimaging rays to pass through.

In order to facilitate clearness of the parameters represented by thepresent invention and the drawings, it is defined in this specificationand the drawings: T1 is a thickness of the first lens element along theoptical axis; T2 is a thickness of the second lens element along theoptical axis; T3 is a thickness of the third lens element along theoptical axis; T4 is a thickness of the fourth lens element along theoptical axis; T5 is a thickness of the fifth lens element along theoptical axis. G12 is an air gap between the first lens element and thesecond lens element along the optical axis; G23 is an air gap betweenthe second lens element and the third lens element along the opticalaxis; G34 is an air gap between the third lens element and the fourthlens element along the optical axis; G45 is an air gap between thefourth lens element and the fifth lens element along the optical axis.ALT is a sum of thicknesses of all the five lens elements along theoptical axis. AAG is a sum of four air gaps from the first lens elementto the fifth lens element along the optical axis. In addition, TTL is adistance from the object-side surface of the first lens element to animage plane along the optical axis, and that is the system length of theoptical imaging lens; EFL is an effective focal length of the opticalimaging lens; TL is a distance from the object-side surface of the firstlens element to the image-side surface of the fifth lens element alongthe optical axis. BFL is a distance from the image-side surface of thefifth lens element to the image plane along the optical axis.

In one embodiment, an optical axis region of the image-side surface ofthe first lens element is concave, a periphery region of the image-sidesurface of the fourth lens element is concave, an optical axis region ofthe object-side surface of the fifth lens element is convex and aperiphery region of the image-side surface of the fifth lens element isconvex. Only the above-mentioned five lens elements of the opticalimaging lens have refracting power, and the optical imaging lenssatisfies the relationship: 1.1≤EFL/TTL≤1.6.

In the optical imaging lens of the present invention, the embodimentsmay also selectively satisfy the following optical conditions:

1. The optical imaging lens is a prime lens;

2. ALT/(T1+G34)≤3.300;

3. (T1+G12)/(T4+T5)≥2.000;

4. T1/(G23+G34+G45)≥2.500;

5. ALT/(G12+T3)≤2.300;

6. AAG/(T3+G34)≤2.000;

7. BFL/(G12+G45)≤5.500;

8. (T1+G34)/T2≥4.700;

9. TL/(T1+G23)≥2.900;

10. BFL/(T4+T5)≥5.200;

11. EFL/(T1+T3+T5)≤5.300;

12. (G12+T2)/T4≥3.200;

13. EFL/AAG≥5.700;

14. TTL/(T1+G12)≤5.500;

15. (T1+T3)/T2≥6.500;

16. T3/(G34+G45)≥2.000;

17. T1/(G23+G34)≥2.500;

18. ALT/(G45+T5)≥5.200;

19. (G12+G23)/G34≥2.600.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 illustrates the methods for determining the surface shapes andfor determining one region is a region in a vicinity of the optical axisor the region in a vicinity of its periphery of one lens element.

FIG. 6 illustrates a first example of the optical imaging lens of thepresent invention.

FIG. 7A illustrates the longitudinal spherical aberration on the imageplane of the first example.

FIG. 7B illustrates the field curvature on the sagittal direction of thefirst example.

FIG. 7C illustrates the field curvature on the tangential direction ofthe first example.

FIG. 7D illustrates the distortion of the first example.

FIG. 8 illustrates a second example of the optical imaging lens of thepresent invention.

FIG. 9A illustrates the longitudinal spherical aberration on the imageplane of the second example.

FIG. 9B illustrates the field curvature on the sagittal direction of thesecond example.

FIG. 9C illustrates the field curvature on the tangential direction ofthe second example.

FIG. 9D illustrates the distortion of the second example.

FIG. 10 illustrates a third example of the optical imaging lens of thepresent invention.

FIG. 11A illustrates the longitudinal spherical aberration on the imageplane of the third example.

FIG. 11B illustrates the field curvature on the sagittal direction ofthe third example.

FIG. 11C illustrates the field curvature on the tangential direction ofthe third example.

FIG. 11D illustrates the distortion of the third example.

FIG. 12 illustrates a fourth example of the optical imaging lens of thepresent invention.

FIG. 13A illustrates the longitudinal spherical aberration on the imageplane of the fourth example.

FIG. 13B illustrates the field curvature on the sagittal direction ofthe fourth example.

FIG. 13C illustrates the field curvature on the tangential direction ofthe fourth example.

FIG. 13D illustrates the distortion of the fourth example.

FIG. 14 illustrates a fifth example of the optical imaging lens of thepresent invention.

FIG. 15A illustrates the longitudinal spherical aberration on the imageplane of the fifth example.

FIG. 15B illustrates the field curvature on the sagittal direction ofthe fifth example.

FIG. 15C illustrates the field curvature on the tangential direction ofthe fifth example.

FIG. 15D illustrates the distortion of the fifth example.

FIG. 16 illustrates a sixth example of the optical imaging lens of thepresent invention.

FIG. 17A illustrates the longitudinal spherical aberration on the imageplane of the sixth example.

FIG. 17B illustrates the field curvature on the sagittal direction ofthe sixth example.

FIG. 17C illustrates the field curvature on the tangential direction ofthe sixth example.

FIG. 17D illustrates the distortion of the sixth example.

FIG. 18 shows the optical data of the first example of the opticalimaging lens.

FIG. 19 shows the aspheric surface data of the first example.

FIG. 20 shows the optical data of the second example of the opticalimaging lens.

FIG. 21 shows the aspheric surface data of the second example.

FIG. 22 shows the optical data of the third example of the opticalimaging lens.

FIG. 23 shows the aspheric surface data of the third example.

FIG. 24 shows the optical data of the fourth example of the opticalimaging lens.

FIG. 25 shows the aspheric surface data of the fourth example.

FIG. 26 shows the optical data of the fifth example of the opticalimaging lens.

FIG. 27 shows the aspheric surface data of the fifth example.

FIG. 28 shows the optical data of the sixth example of the opticalimaging lens.

FIG. 29 shows the aspheric surface data of the sixth example.

FIG. 30 shows some important ratios in the examples.

FIG. 31 shows some important ratios in the examples.

DETAILED DESCRIPTION

In the present disclosure, the optical system may comprise at least onelens element to receive imaging rays that are incident on the opticalsystem over a set of angles ranging from parallel to an optical axis toa half field of view (HFOV) angle with respect to the optical axis. Theimaging rays pass through the optical system to produce an image on animage plane. The term “a lens element having positive refracting power(or negative refracting power)” means that the paraxial refracting powerof the lens element in Gaussian optics is positive (or negative). Theterm “an object-side (or image-side) surface of a lens element” refersto a specific region of that surface of the lens element at whichimaging rays can pass through that specific region. Imaging rays includeat least two types of rays: a chief ray Lc and a marginal ray Lm (asshown in FIG. 1). An object-side (or image-side) surface of a lenselement can be characterized as having several regions, including anoptical axis region, a periphery region, and, in some cases, one or moreintermediate regions, as discussed more fully below.

FIG. 1 is a radial cross-sectional view of a lens element 100. Tworeferential points for the surfaces of the lens element 100 can bedefined: a central point, and a transition point. The central point of asurface of a lens element is a point of intersection of that surface andthe optical axis I. As illustrated in FIG. 1, a first central point CP1may be present on the object-side surface 110 of lens element 100 and asecond central point CP2 may be present on the image-side surface 120 ofthe lens element 100. The transition point is a point on a surface of alens element, at which the line tangent to that point is perpendicularto the optical axis I. The optical boundary OB of a surface of the lenselement is defined as a point at which the radially outermost marginalray Lm passing through the surface of the lens element intersects thesurface of the lens element. All transition points lie between theoptical axis I and the optical boundary OB of the surface of the lenselement. If multiple transition points are present on a single surface,then these transition points are sequentially named along the radialdirection of the surface with reference numerals starting from the firsttransition point. For example, the first transition point, e.g., TP1,(closest to the optical axis I), the second transition point, e.g., TP2,(as shown in FIG. 4), and the Nth transition point (farthest from theoptical axis I).

The region of a surface of the lens element from the central point tothe first transition point TP1 is defined as the optical axis region,which includes the central point. The region located radially outside ofthe farthest Nth transition point from the optical axis I to the opticalboundary OB of the surface of the lens element is defined as theperiphery region. In some embodiments, there may be intermediate regionspresent between the optical axis region and the periphery region, withthe number of intermediate regions depending on the number of thetransition points.

The shape of a region is convex if a collimated ray being parallel tothe optical axis I and passing through the region is bent toward theoptical axis I such that the ray intersects the optical axis I on theimage side A2 of the lens element. The shape of a region is concave ifthe extension line of a collimated ray being parallel to the opticalaxis I and passing through the region intersects the optical axis I onthe object side A1 of the lens element.

Additionally, referring to FIG. 1, the lens element 100 may also have amounting portion 130 extending radially outward from the opticalboundary OB. The mounting portion 130 is typically used to physicallysecure the lens element to a corresponding element of the optical system(not shown). Imaging rays do not reach the mounting portion 130. Thestructure and shape of the mounting portion 130 are only examples toexplain the technologies, and should not be taken as limiting the scopeof the present disclosure. The mounting portion 130 of the lens elementsdiscussed below may be partially or completely omitted in the followingdrawings.

Referring to FIG. 2, optical axis region Z1 is defined between centralpoint CP and first transition point TP1. Periphery region Z2 is definedbetween TP1 and the optical boundary OB of the surface of the lenselement. Collimated ray 211 intersects the optical axis I on the imageside A2 of lens element 200 after passing through optical axis regionZ1, i.e., the focal point of collimated ray 211 after passing throughoptical axis region Z1 is on the image side A2 of the lens element 200at point R in FIG. 2. Accordingly, since the ray itself intersects theoptical axis I on the image side A2 of the lens element 200, opticalaxis region Z1 is convex. On the contrary, collimated ray 212 divergesafter passing through periphery region Z2. The extension line EL ofcollimated ray 212 after passing through periphery region Z2 intersectsthe optical axis I on the object side A1 of lens element 200, i.e., thefocal point of collimated ray 212 after passing through periphery regionZ2 is on the object side A1 at point M in FIG. 2. Accordingly, since theextension line EL of the ray intersects the optical axis I on the objectside A1 of the lens element 200, periphery region Z2 is concave. In thelens element 200 illustrated in FIG. 2, the first transition point TP1is the border of the optical axis region and the periphery region, i.e.,TP1 is the point at which the shape changes from convex to concave.

Alternatively, there is another way for a person having ordinary skillin the art to determine whether an optical axis region is convex orconcave by referring to the sign of “Radius” (the “R” value), which isthe paraxial radius of shape of a lens surface in the optical axisregion. The R value is commonly used in conventional optical designsoftware such as Zemax and CodeV. The R value usually appears in thelens data sheet in the software. For an object-side surface, a positiveR value defines that the optical axis region of the object-side surfaceis convex, and a negative R value defines that the optical axis regionof the object-side surface is concave. Conversely, for an image-sidesurface, a positive R value defines that the optical axis region of theimage-side surface is concave, and a negative R value defines that theoptical axis region of the image-side surface is convex. The resultfound by using this method should be consistent with the methodutilizing intersection of the optical axis by rays/extension linesmentioned above, which determines surface shape by referring to whetherthe focal point of a collimated ray being parallel to the optical axis Iis on the object-side or the image-side of a lens element. As usedherein, the terms “a shape of a region is convex (concave),” “a regionis convex (concave),” and “a convex- (concave-) region,” can be usedalternatively.

FIG. 3, FIG. 4 and FIG. 5 illustrate examples of determining the shapeof lens element regions and the boundaries of regions under variouscircumstances, including the optical axis region, the periphery region,and intermediate regions as set forth in the present specification.

FIG. 3 is a radial cross-sectional view of a lens element 300. Asillustrated in FIG. 3, only one transition point TP1 appears within theoptical boundary OB of the image-side surface 320 of the lens element300. Optical axis region Z1 and periphery region Z2 of the image-sidesurface 320 of lens element 300 are illustrated. The R value of theimage-side surface 320 is positive (i.e., R>0). Accordingly, the opticalaxis region Z1 is concave.

In general, the shape of each region demarcated by the transition pointwill have an opposite shape to the shape of the adjacent region(s).Accordingly, the transition point will define a transition in shape,changing from concave to convex at the transition point or changing fromconvex to concave. In FIG. 3, since the shape of the optical axis regionZ1 is concave, the shape of the periphery region Z2 will be convex asthe shape changes at the transition point TP1.

FIG. 4 is a radial cross-sectional view of a lens element 400. Referringto FIG. 4, a first transition point TP1 and a second transition pointTP2 are present on the object-side surface 410 of lens element 400. Theoptical axis region Z1 of the object-side surface 410 is defined betweenthe optical axis I and the first transition point TP1. The R value ofthe object-side surface 410 is positive (i.e., R>0). Accordingly, theoptical axis region Z1 is convex.

The periphery region Z2 of the object-side surface 410, which is alsoconvex, is defined between the second transition point TP2 and theoptical boundary OB of the object-side surface 410 of the lens element400. Further, intermediate region Z3 of the object-side surface 410,which is concave, is defined between the first transition point TP1 andthe second transition point TP2. Referring once again to FIG. 4, theobject-side surface 410 includes an optical axis region Z1 locatedbetween the optical axis I and the first transition point TP1, anintermediate region Z3 located between the first transition point TP1and the second transition point TP2, and a periphery region Z2 locatedbetween the second transition point TP2 and the optical boundary OB ofthe object-side surface 410. Since the shape of the optical axis regionZ1 is designed to be convex, the shape of the intermediate region Z3 isconcave as the shape of the intermediate region Z3 changes at the firsttransition point TP1, and the shape of the periphery region Z2 is convexas the shape of the periphery region Z2 changes at the second transitionpoint TP2.

FIG. 5 is a radial cross-sectional view of a lens element 500. Lenselement 500 has no transition point on the object-side surface 510 ofthe lens element 500. For a surface of a lens element with no transitionpoint, for example, the object-side surface 510 the lens element 500,the optical axis region Z1 is defined as the region between 0-50% of thedistance between the optical axis I and the optical boundary OB of thesurface of the lens element and the periphery region is defined as theregion between 50%-100% of the distance between the optical axis I andthe optical boundary OB of the surface of the lens element. Referring tolens element 500 illustrated in FIG. 5, the optical axis region Z1 ofthe object-side surface 510 is defined between the optical axis I and50% of the distance between the optical axis I and the optical boundaryOB. The R value of the object-side surface 510 is positive (i.e., R>0).Accordingly, the optical axis region Z1 is convex. For the object-sidesurface 510 of the lens element 500, because there is no transitionpoint, the periphery region Z2 of the object-side surface 510 is alsoconvex. It should be noted that lens element 500 may have a mountingportion (not shown) extending radially outward from the periphery regionZ2.

As shown in FIG. 6, the optical imaging lens 1 of five lens elements ofthe present invention, sequentially located from an object side A1(where an object is located) to an image side A2 along an optical axisI, has a first lens element 10, an aperture 80, a second lens element20, a third lens element 30, a fourth lens element 40, a fifth lenselement 50 and an image plane 91. Generally speaking, the first lenselement 10, the second lens element 20, the third lens element 30, thefourth lens element 40 and the fifth lens element 50 may be made of atransparent plastic material but the present invention is not limited tothis, and each lens element has an appropriate refracting power. In thepresent invention, lens elements having refracting power included by theoptical imaging lens 1 are only the five lens elements (the first lenselement 10, the second lens element 20, the third lens element 30, thefourth lens element 40 and the fifth lens element 50) described above.The optical axis I is the optical axis of the entire optical imaginglens 1, and the optical axis of each of the lens elements coincides withthe optical axis of the optical imaging lens 1.

Furthermore, the optical imaging lens 1 includes an aperture 80 disposedin an appropriate position. In FIG. 6, the aperture 80 is disposedbetween the first lens element 10 and the second lens element 20. Whenlight emitted or reflected by an object (not shown) which is located atthe object side A1 enters the optical imaging lens 1 of the presentinvention, it forms a clear and sharp image on the image plane 91 at theimage side A2 after passing through the first lens element 10, theaperture 80, the second lens element 20, the third lens element 30, thefourth lens element 40, the fifth lens element 50 and the filter 90. Inone embodiment of the present invention, the filter 90 may be a filterof various suitable functions to filter out light of a specificwavelength, for example an infrared cut-off filter, and is placedbetween the fifth lens element 50 and the image plane 91.

The first lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40 and the fifth lens element 50 ofthe optical imaging lens 1 each has an object-side surface 11, 21, 31,41 and 51 facing toward the object side A1 and allowing imaging rays topass through as well as an image-side surface 12, 22, 32, 42 and 52facing toward the image side A2 and allowing the imaging rays to passthrough. Furthermore, each object-side surface and image-side surface oflens elements in the optical imaging lens 1 of present invention has anoptical axis region and a periphery region.

Each lens element in the optical imaging lens 1 of the present inventionfurther has a thickness T along the optical axis I. For embodiment, thefirst lens element 10 has a first lens element thickness T1, the secondlens element 20 has a second lens element thickness T2, the third lenselement 30 has a third lens element thickness T3, the fourth lenselement 40 has a fourth lens element thickness T4 and the fifth lenselement 50 has a fifth lens element thickness T5. Therefore, a sum ofthicknesses of all the five lens elements in the optical imaging lens 1along the optical axis I is ALT=T1+T2+T3+T4+T5.

In addition, between two adjacent lens elements in the optical imaginglens 1 of the present invention there may be an air gap along theoptical axis I. In the embodiments, there is an air gap G12 between thefirst lens element 10 and the second lens element 20, an air gap G23between the second lens element 20 and the third lens element 30, an airgap G34 between the third lens element 30 and the fourth lens element 40and air gap G45 between the fourth lens element 40 and the fifth lenselement 50. Therefore, a sum of four air gaps from the first lenselement 10 to the fifth lens element 50 along the optical axis I isAAG=G12+G23+G34+G45.

In addition, a distance from the object-side surface 11 of the firstlens element 10 to the image plane 91 along the optical axis I is TTL,namely a system length of the optical imaging lens 1; an effective focallength of the optical imaging lens is EFL; a distance from theobject-side surface 11 of the first lens element 10 to the image-sidesurface 52 of the fifth lens element 50 along the optical axis I is TL.

An air gap between the image-side surface 52 of the fifth lens element50 and the filter 90 along the optical axis I is G5F when the filter 90is placed between the fifth lens element 50 and the image plane 91; athickness of the filter 90 along the optical axis I is TF; an air gapbetween the filter 90 and the image plane 91 along the optical axis I isGFP; and a distance from the image-side surface 52 of the fifth lenselement 50 to the image plane 91 along the optical axis I, namely theback focal length is BFL. Therefore, BFL=G5F+TF+GFP. ImgH is an imageheight of the optical imaging lens 1.

Furthermore, a focal length of the first lens element 10 is f1; a focallength of the second lens element 20 is f2; a focal length of the thirdlens element 30 is f3; a focal length of the fourth lens element 40 isf4; a focal length of the fifth lens element 50 is f5; a refractiveindex of the first lens element 10 is n1; a refractive index of thesecond lens element 20 is n2; a refractive index of the third lenselement 30 is n3; a refractive index of the fourth lens element 40 isn4; a refractive index of the fifth lens element 50 is n5; an Abbenumber of the first lens element 10 is υ1; an Abbe number of the secondlens element 20 is υ2; an Abbe number of the third lens element 30 isυ3; an Abbe number of the fourth lens element 40 is υ4 and an Abbenumber of the fifth lens element 50 is υ5.

First Embodiment

Please refer to FIG. 6 which illustrates the first embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG. 7Afor the longitudinal spherical aberration on the image plane 91 of thefirst embodiment; please refer to FIG. 7B for the field curvatureaberration on the sagittal direction; please refer to FIG. 7C for thefield curvature aberration on the tangential direction; and please referto FIG. 7D for the distortion aberration. The Y axis of the sphericalaberration in each embodiment is “field of view” for 1.0. The Y axis ofthe field curvature aberration and the distortion aberration in eachembodiment stands for the “image height” (ImgH), which is 2.805 mm.

The optical imaging lens 1 of the first embodiment is mainly composed offive lens elements 10, 20, 30, 40 and 50 with refracting power, anaperture 80, and an image plane 91. Only the five lens elements 10, 20,30, 40 and 50 of the optical imaging lens 1 of the first embodiment haverefracting power. The aperture 80 is provided between the first lenselement 10 and the second lens element 20.

The first lens element 10 has positive refracting power. An optical axisregion 13 and a periphery region 14 of the object-side surface 11 of thefirst lens element 10 are convex. An optical axis region 16 and aperiphery region 17 of the image-side surface 12 of the first lenselement 10 are concave. Besides, both the object-side surface 11 and theimage-side surface 12 of the first lens element 10 are asphericalsurfaces, but it is not limited thereto.

The second lens element 20 has negative refracting power. An opticalaxis region 23 and a periphery region 24 of the object-side surface 21of the second lens element 20 are convex. An optical axis region 26 anda periphery region 27 of the image-side surface 22 of the second lenselement 20 are concave. Besides, both the object-side surface 21 and theimage-side surface 22 of the second lens element 20 are asphericalsurfaces, but it is not limited thereto.

The third lens element 30 has positive refracting power. An optical axisregion 33 and a periphery region 34 of the object-side surface 31 of thethird lens element 30 are convex. An optical axis region 36 and aperiphery region 37 of the image-side surface 32 of the third lenselement 30 are concave. Besides, both the object-side surface 31 and theimage-side surface 32 of the third lens element 30 are asphericalsurfaces, but it is not limited thereto.

The fourth lens element 40 has negative refracting power. An opticalaxis region 43 and a periphery region 44 of the object-side surface 41of the fourth lens element 40 are concave. An optical axis region 46 anda periphery region 47 of the image-side surface 42 of the fourth lenselement 40 are concave. Besides, both the object-side surface 41 and theimage-side surface 42 of the fourth lens element 40 are asphericalsurfaces, but it is not limited thereto.

The fifth lens element 50 has positive refracting power. An optical axisregion 53 and a periphery region 54 of the object-side surface 51 of thefifth lens element 50 are convex. An optical axis region 56 and aperiphery region 57 of the image-side surface 52 of the fifth lenselement 50 are convex. Besides, both the object-side surface 51 and theimage-side surface 52 of the fifth lens element 50 are asphericalsurfaces, but it is not limited thereto.

In the first lens element 10, the second lens element 20, the third lenselement 30, the fourth lens element 40, the fifth lens element 50 of theoptical imaging lens element 1 of the present invention, there are 10surfaces, such as the object-side surfaces 11/21/31/41/51 and theimage-side surfaces 12/22/32/42/52 are aspherical, but it is not limitedthereto. If a surface is aspherical, these aspheric coefficients aredefined according to the following formula:

${Z(Y)} = {{\frac{Y^{2}}{R}\text{/}\left( {1 + \sqrt{1 - {\left( {1 + K} \right)\frac{Y^{2}}{R^{2}}}}} \right)} + {\sum\limits_{i = 1}^{n}\;{a_{2i} \times Y^{2i}}}}$In which:

R represents the curvature radius of the lens element surface;

Z represents the depth of an aspherical surface (the perpendiculardistance between the point of the aspherical surface at a distance Yfrom the optical axis I and the tangent plane of the vertex on theoptical axis I of the aspherical surface);

Y represents a vertical distance from a point on the aspherical surfaceto the optical axis I;

K is a conic constant; and

a_(2i) is the aspheric coefficient of the 2i^(th) order.

The optical data of the first embodiment of the optical imaging lens 1are shown in FIG. 18 while the aspheric surface data are shown in FIG.19. In the present embodiments of the optical imaging lens, the f-numberof the entire optical imaging lens is Fno, EFL is the effective focallength, HFOV stands for the half field of view of the entire opticalimaging lens, and the unit for the radius, the thickness and the focallength is in millimeters (mm). In this embodiment, TTL=12.895 mm;EFL=14.307 mm; HFOV=10.878 degrees; ImgH=2.805 mm; Fno=3.482.

Second Embodiment

Please refer to FIG. 8 which illustrates the second embodiment of theoptical imaging lens 1 of the present invention. It is noted that fromthe second embodiment to the following embodiments, in order to simplifythe figures, only the components different from what the firstembodiment has, and the basic lens elements will be labeled in figures.Other components that are the same as what the first embodiment has,such as a convex surface or a concave surface, are omitted in thefollowing embodiments. Please refer to FIG. 9A for the longitudinalspherical aberration on the image plane 91 of the second embodiment,please refer to FIG. 9B for the field curvature aberration on thesagittal direction, please refer to FIG. 9C for the field curvatureaberration on the tangential direction, and please refer to FIG. 9D forthe distortion aberration. The components in this embodiment are similarto those in the first embodiment, but the optical data such as therefracting power, the radius, the lens thickness, the aspheric surfaceor the back focal length in this embodiment are different from theoptical data in the first embodiment. Besides, in this embodiment, anoptical axis region 36 and a periphery region 37 of the image-sidesurface 32 of the third lens element 30 are convex and an optical axisregion 56 of the image-side surface 52 of the fifth lens element 50 isconcave.

The optical data of the second embodiment of the optical imaging lensare shown in FIG. 20 while the aspheric surface data are shown in FIG.21. In this embodiment, TTL=12.865 mm; EFL=14.292 mm; HFOV=10.878degrees; ImgH=2.805 mm; Fno=3.770. In particular, the TTL of the opticalimaging lens in this embodiment is shorter than that of the opticalimaging lens in the first embodiment.

Third Embodiment

Please refer to FIG. 10 which illustrates the third embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.11A for the longitudinal spherical aberration on the image plane 91 ofthe third embodiment; please refer to FIG. 11B for the field curvatureaberration on the sagittal direction; please refer to FIG. 11C for thefield curvature aberration on the tangential direction; and please referto FIG. 11D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the refracting power, the radius, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. Besides, inthis embodiment, an optical axis region 23 and a periphery region 24 ofthe object-side surface 21 of the second lens element 20 are concave andan optical axis region 36 of the image-side surface 32 of the third lenselement 30 is convex.

The optical data of the third embodiment of the optical imaging lens areshown in FIG. 22 while the aspheric surface data are shown in FIG. 23.In this embodiment, TTL=13.174 mm; EFL=14.518 mm; HFOV=10.878 degrees;ImgH=2.800 mm; Fno=4.218. In particular, the distortion aberration ofthe optical imaging lens in this embodiment is better than that of theoptical imaging lens in the first embodiment.

Fourth Embodiment

Please refer to FIG. 12 which illustrates the fourth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.13A for the longitudinal spherical aberration on the image plane 91 ofthe fourth embodiment; please refer to FIG. 13B for the field curvatureaberration on the sagittal direction; please refer to FIG. 13C for thefield curvature aberration on the tangential direction; and please referto FIG. 13D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the refracting power, the radius, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. Besides, inthis embodiment, an optical axis region 23 and a periphery region 24 ofthe object-side surface 21 of the second lens element 20 are concave andan optical axis region 36 and a periphery region 37 of the image-sidesurface 32 of the third lens element 30 are convex.

The optical data of the fourth embodiment of the optical imaging lensare shown in FIG. 24 while the aspheric surface data are shown in FIG.25. In this embodiment, TTL=12.514 mm; EFL=14.501 mm; HFOV=10.878degrees; ImgH=2.801 mm; Fno=3.670. In particular, 1) the TTL in thisembodiment is shorter than that of the optical imaging lens in the firstembodiment, 2) the field curvature aberration on the sagittal directionof the optical imaging lens in this embodiment is better than that ofthe optical imaging lens in the first embodiment, and 3) the distortionaberration of the optical imaging lens in this embodiment is better thanthat of the optical imaging lens in the first embodiment.

Fifth Embodiment

Please refer to FIG. 14 which illustrates the fifth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.15A for the longitudinal spherical aberration on the image plane 91 ofthe fifth embodiment; please refer to FIG. 15B for the field curvatureaberration on the sagittal direction; please refer to FIG. 15C for thefield curvature aberration on the tangential direction, and please referto FIG. 15D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the refracting power, the radius, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. Besides, inthis embodiment, a periphery region 24 of the object-side surface 21 ofthe second lens element 20 is concave.

The optical data of the fifth embodiment of the optical imaging lens areshown in FIG. 26 while the aspheric surface data are shown in FIG. 27.In this embodiment, TTL=12.946 mm; EFL=14.393 mm; HFOV=10.878 degrees;ImgH=2.800 mm; Fno=3.375. In particular, 1) the Fno in this embodimentis smaller than that of the optical imaging lens in the firstembodiment, 2) the longitudinal spherical aberration of the opticalimaging lens in this embodiment is better than that of the opticalimaging lens in the first embodiment, 3) the field curvature aberrationon the sagittal direction of the optical imaging lens in this embodimentis better than that of the optical imaging lens in the first embodiment,and 4) the distortion aberration of the optical imaging lens in thisembodiment is better than that of the optical imaging lens in the firstembodiment.

Sixth Embodiment

Please refer to FIG. 16 which illustrates the sixth embodiment of theoptical imaging lens 1 of the present invention. Please refer to FIG.17A for the longitudinal spherical aberration on the image plane 91 ofthe sixth embodiment; please refer to FIG. 17B for the field curvatureaberration on the sagittal direction; please refer to FIG. 17C for thefield curvature aberration on the tangential direction, and please referto FIG. 17D for the distortion aberration. The components in thisembodiment are similar to those in the first embodiment, but the opticaldata such as the refracting power, the radius, the lens thickness, theaspheric surface or the back focal length in this embodiment aredifferent from the optical data in the first embodiment. Besides, inthis embodiment, a periphery region 17 of the image-side surface 12 ofthe first lens element 10 is convex, a periphery region 24 of theobject-side surface 21 of the second lens element 20 is concave, aperiphery region 37 of the image-side surface 32 of the third lenselement 30 is convex, a periphery region 54 of the object-side surface51 of the fifth lens element 50 is concave and an optical axis region 56of the image-side surface 52 of the fifth lens element 50 is concave.

The optical data of the sixth embodiment of the optical imaging lens areshown in FIG. 28 while the aspheric surface data are shown in FIG. 29.In this embodiment, TTL=11.730 mm; EFL=14.606 mm; HFOV=10.878 degrees;ImgH=2.808 mm; Fno=3.358. In particular, 1) the TTL in this embodimentis shorter than that of the optical imaging lens in the firstembodiment; 2) the Fno of the optical imaging lens in this embodiment issmaller than that of the optical imaging lens in the first embodiment;and 3) the distortion aberration of the optical imaging lens in thisembodiment is better than that of the optical imaging lens in the firstembodiment.

Some important ratios in each embodiment are shown in FIG. 30 and inFIG. 31.

The numeral value ranges within the maximum and minimum values obtainedfrom the combination ratio relationships of the optical parametersdisclosed in each embodiment of the invention can all be implementedaccordingly.

Each embodiment of the present invention provides an optical imaginglens which has a zoom-in function and good imaging quality. For example,the following lens curvature configuration may effectively reduce thefield curvature aberration and the distortion aberration to optimize theimaging quality of the optical imaging lens. Furthermore, the presentinvention has the corresponding advantages:

1. An optical axis region 16 of the image-side surface 12 of the firstlens element 10 is concave, a periphery region 47 of the image-sidesurface 42 of the fourth lens element 40 is concave, an optical axisregion 53 of the object-side surface 51 of the fifth lens element 50 isconvex and a periphery region 57 of the image-side surface 52 of thefifth lens element 50 is convex.2. The satisfaction of the conditional formula 1.1≤EFL/TTL≤1.6 to gowith the above lens curvature configuration may equip the opticalimaging lens 1 with the desirable zoom-in function as well as maintaingood imaging quality.3. If a reflecting element is placed in front of the first lens element10 to make the light path more circuitous, the optical imaging lens 1may be applied in various electronic devices.4. The optical imaging lens 1 is a prime lens to go with that an opticalaxis region 16 of the image-side surface 12 of the first lens element 10is concave, a periphery region 47 of the image-side surface 42 of thefourth lens element 40 is concave, an optical axis region 53 of theobject-side surface 51 of the fifth lens element 50 is convex and aperiphery region 57 of the image-side surface 52 of the fifth lenselement 50 is convex and may result in better manufacturing yield, andit is easier to maintain and control the optical imaging quality. Aprime lens design helps reduce the size of the optical imaging lens 1 tomeet the requirement of miniature of a portable electronic device.5. In order to reduce the system length of the optical imaging lens 1along the optical axis I and simultaneously to ensure the imagingquality, the air gaps between the adjacent lens elements or thethickness of each lens element should be appropriately adjusted.However, the assembly or the manufacturing difficulty should be takeninto consideration as well. If the following numerical conditions areselectively satisfied, the optical imaging lens 1 of the presentinvention may have better optical arrangements:1) ALT/(T1+G34)≤3.300, and the preferable range is1.700≤ALT/(T1+G34)≤3.300;2) (T1+G12)/(T4+T5)≥2.000, and the preferable range is2.000≤(T1+G12)/(T4+T5)≤4.000;3) T1/(G23+G34+G45)≥2.500, and the preferable range is2.500≤T1/(G23+G34+G45)≤4.000;4) ALT/(G12+T3)≤2.300, and the preferable range is1.100≤ALT/(G12+T3)≤2.300;5) AAG/(T3+G34)≤2.000, and the preferable range is0.400≤AAG/(T3+G34)≤2.000;6) BFL/(G12+G45)≤5.500, and the preferable range is2.800≤BFL/(G12+G45)≤5.500;7) (T1+G34)/T2≥4.700, and the preferable range is4.700≤(T1+G34)/T2≤10.600;8) TL/(T1+G23)≥2.900, and the preferable range is2.900≤TL/(T1+G23)≤5.200;9) BFL/(T4+T5)≥5.200, and the preferable range is5.200≤BFL/(T4+T5)≤7.300;10) EFL/(T1+T3+T5)≤5.300, and the preferable range is3.100≤EFL/(T1+T3+T5)≤5.300;11) (G12+T2)/T4≥3.200, and the preferable range is3.200≤(G12+T2)/T4≤6.900;12) EFL/AAG≥5.700, and the preferable range is 5.700≤EFL/AAG≤10.500;13) TTL/(T1+G12)≤5.500, and the preferable range is3.500≤TTL/(T1+G12)≤5.500;14) (T1+T3)/T2≥6.500, and the preferable range is6.500≤(T1+T3)/T2≤15.000;15) T3/(G34+G45)≥2.000, and the preferable range is2.000≤T3/(G34+G45)≤7.000;16) T1/(G23+G34)≥2.500, and the preferable range is2.500≤T1/(G23+G34)≤6.800;17) ALT/(G45+T5)≥5.200, and the preferable range is5.200≤ALT/(G45+T5)≤7.300;18) (G12+G23)/G34≥2.600, and the preferable range is2.600≤(G12+G23)/G34≤8.100.

By observing three representative wavelengths of 470 nm, 555 nm and 650nm in each embodiment of the present invention, it is suggested off-axislight of different heights of every wavelength all concentrates on theimage plane, and deviations of every curve also reveal that off-axislight of different heights are well controlled so the examples doimprove the spherical aberration, the astigmatic aberration and thedistortion aberration. In addition, by observing the imaging qualitydata the distances amongst the three representing different wavelengthsof 470 nm, 555 nm and 650 nm are pretty close to one another, whichmeans the embodiments of the present invention are able to concentratelight of the three representing different wavelengths so that theaberration is greatly improved. Given the above, it is understood thatthe embodiments of the present invention provides outstanding imagingquality.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. An optical imaging lens, from an object side toan image side in order along an optical axis comprising: a first lenselement, a second lens element, a third lens element, a fourth lenselement, and a fifth lens element, the first lens element to the fifthlens element each having an object-side surface facing toward the objectside and allowing imaging rays to pass through as well as an image-sidesurface facing toward the image side and allowing the imaging rays topass through, wherein: an optical axis region of the image-side surfaceof the first lens element is concave; a periphery region of theimage-side surface of the fourth lens element is concave; and an opticalaxis region of the object-side surface of the fifth lens element isconvex and a periphery region of the image-side surface of the fifthlens element is convex; wherein only the above-mentioned five lenselements of the optical imaging lens have refracting power; wherein EFLis an effective focal length of the optical imaging lens, T1 is athickness of the first lens element along the optical axis, G12 is anair gap between the first lens element and the second lens element alongthe optical axis, and TTL is a distance from the object-side surface ofthe first lens element to an image plane along the optical axis, and theoptical imaging lens satisfies the relationship: 1.1≤EFL/TTL≤1.6 andTTL/(T1+G12)≤5.500.
 2. The optical imaging lens of claim 1, being aprime lens.
 3. The optical imaging lens of claim 1, wherein ALT is a sumof thicknesses of all the five lens elements along the optical axis, andG34 is an air gap between the third lens element and the fourth lenselement along the optical axis, and the optical imaging lens satisfiesthe relationship: ALT/(T1+G34)≤3.300.
 4. The optical imaging lens ofclaim 1, wherein T4 is a thickness of the fourth lens element along theoptical axis, T5 is a thickness of the fifth lens element along theoptical axis, and the optical imaging lens satisfies the relationship:(T1+G12)/(T4+T5)≥2.000.
 5. The optical imaging lens of claim 1, whereinG23 is an air gap between the second lens element and the third lenselement along the optical axis, G34 is an air gap between the third lenselement and the fourth lens element along the optical axis and G45 is anair gap between the fourth lens element and the fifth lens element alongthe optical axis, and the optical imaging lens satisfies therelationship: T1/(G23+G34+G45)≥2.500.
 6. The optical imaging lens ofclaim 1, wherein ALT is a sum of thicknesses of all the five lenselements along the optical axis, T3 is a thickness of the third lenselement along the optical axis and the optical imaging lens satisfiesthe relationship: ALT/(G12+T3)≤2.300.
 7. The optical imaging lens ofclaim 1, wherein AAG is a sum of four air gaps from the first lenselement to the fifth lens element along the optical axis, T3 is athickness of the third lens element along the optical axis and G34 is anair gap between the third lens element and the fourth lens element alongthe optical axis, and the optical imaging lens satisfies therelationship: AAG/(T3+G34)≤2.000.
 8. The optical imaging lens of claim1, wherein BFL is a distance from the image-side surface of the fifthlens element to an image plane along the optical axis, and G45 is an airgap between the fourth lens element and the fifth lens element along theoptical axis, and the optical imaging lens satisfies the relationship:BFL/(G12+G45)≤5.500.
 9. The optical imaging lens of claim 1, wherein T2is a thickness of the second lens element along the optical axis and G34is an air gap between the third lens element and the fourth lens elementalong the optical axis, and the optical imaging lens satisfies therelationship: (T1+G34)/T2≥4.700.
 10. The optical imaging lens of claim1, wherein TL is a distance from the object-side surface of the firstlens element to the image-side surface of the fifth lens element alongthe optical axis G23 is an air gap between the second lens element andthe third lens element along the optical axis, and the optical imaginglens satisfies the relationship: TL/(T1+G23)≥2.900.
 11. The opticalimaging lens of claim 1, wherein BFL is a distance from the image-sidesurface of the fifth lens element to an image plane along the opticalaxis, T4 is a thickness of the fourth lens element along the opticalaxis and T5 is a thickness of the fifth lens element along the opticalaxis, and the optical imaging lens satisfies the relationship:BFL/(T4+T5)≥5.200.
 12. The optical imaging lens of claim 1, wherein T3is a thickness of the third lens element along the optical axis and T5is a thickness of the fifth lens element along the optical axis, and theoptical imaging lens satisfies the relationship: EFL/(T1+T3+T5)≤5.300.13. The optical imaging lens of claim 1, wherein T2 is a thickness ofthe second lens element along the optical axis, T4 is a thickness of thefourth lens element along the optical axis, and the optical imaging lenssatisfies the relationship: (G12+T2)/T4≥3.200.
 14. The optical imaginglens of claim 1, wherein AAG is a sum of four air gaps from the firstlens element to the fifth lens element along the optical axis, and theoptical imaging lens satisfies the relationship: EFL/AAG≥5.700.
 15. Theoptical imaging lens of claim 1, wherein T1 is a thickness of the firstlens element along the optical axis, T2 is a thickness of the secondlens element along the optical axis and T3 is a thickness of the thirdlens element along the optical axis, and the optical imaging lenssatisfies the relationship: (T1+T3)/T2≥6.500.
 16. The optical imaginglens of claim 1, wherein T3 is a thickness of the third lens elementalong the optical axis, G34 is an air gap between the third lens elementand the fourth lens element along the optical axis and G45 is an air gapbetween the fourth lens element and the fifth lens element along theoptical axis, and the optical imaging lens satisfies the relationship:T3/(G34+G45)≥2.000.
 17. The optical imaging lens of claim 1, wherein G23is an air gap between the second lens element and the third lens elementalong the optical axis and G34 is an air gap between the third lenselement and the fourth lens element along the optical axis, and theoptical imaging lens satisfies the relationship: T1/(G23+G34)≥2.500. 18.The optical imaging lens of claim 1, wherein ALT is a sum of thicknessesof all the five lens elements along the optical axis, T5 is a thicknessof the fifth lens element along the optical axis and G45 is an air gapbetween the fourth lens element and the fifth lens element along theoptical axis, and the optical imaging lens satisfies the relationship:ALT/(G45+T5)≥5.200.
 19. The optical imaging lens of claim 1, wherein G23is an air gap between the second lens element and the third lens elementalong the optical axis and G34 is an air gap between the third lenselement and the fourth lens element along the optical axis, and theoptical imaging lens satisfies the relationship: (G12+G23)/G34≥2.600.